Organic farming could produce enough food to feed large populations, according to British scientists at the Festival of Science in Sheffield.

It may be environmentally friendly, but advocates of modern intensive farming methods say that "going organic" will not produce enough food to feed large populations.

But the British team say the lower yields from organic farms can still be profitable once the savings on chemical additives such as fertilisers and machinery are taken into account. And they say organic farming could be viable even in developing countries if the political climate is favourable.

In developed countries, organic food is increasingly in demand. It is perceived by many as being healthier, and free from chemical residues from pesticides and fertilisers.

Although organic farms achieve only 60 to 80% of the yield of high intensity conventional farms, some of these losses can be offset against savings on expensive fertilisers and insecticides.

Organic farms economically viable

Most organic farms in countries like Britain and the United States are still fairly small in size.

Could organic crops feed the world?

Dr Liz Stockdale, of the Institute of Arable Crop Research in England, believes organic farms could be economically viable on a much larger scale, even in developing countries with large populations.

"In less developed countries, countries where the conventional agricultural systems aren't that intensive to start with, we can see that conventional systems and organic systems actually can match yields very closely," she said.

Dr Stockdale says this is because conventional farms in poorer countries tend to use less expensive machinery and chemicals, putting them more on a par with organic systems.

Growing the right crops

But she says the lower yields of organic farms in any country could be greatly increased as scientists learn more about controlling insects and disease without chemicals, and find the right crops to suit a particular region's pests and climate.

"One of the main problems isn't getting the total yield, it's getting marketable yield, yield that consumers are quite happy to buy. And that's because quite a bit of that crop is damaged by pests or disease, just on the surface but not affecting the quality for eating, but the way it looks".

"So just improving ways of trapping pests is the one that makes us money."

But Dr Stockdale says farmers can do only so much in producing enough food to feed the world; governments have a role to play as well.

Conventional farms, she says, often produce too much food - leading to produce being grown for human consumption in Western countries frequently being fed to animals.

Until governments tackle the social and political factors involved in poverty and effective food distribution, she says, millions of people will continue to go hungry.